SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '586a5fee3dcbc6be0e9b4154d218f15fb21e2f4b31b6078876561d7b6c85b643' 
  AND token = 'mV14+qK5QFptFd9LVwDXA/oXWhU9J2/9VsyL/PE+M8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}